Cartridge case extractor



March 1, 1949. ca. B. NEIDHARDT CARTRIDGE CASE EXTRACTOR Filed Jan. 27,1945 GRAHAM :ELNEIDHAH'DTJ aamvh mw Patented Mar. 1, 1949 UNITED STATESPATENT OFFICE CARTRIDGE CASE EXTRACTOR Graham B. Neidhardt, Albion, Ind.

Application January 27, 1945, Serial No. 574,947

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 1 Claim.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment to me ofany royalty thereon.

The invention relates to cartridge case extractors.

In some guns such as the 20 mm. aircraft cannon, the standard extractorserves to aid in positioning the round as it is carried into the chamberby the bolt to prevent the round from entering the chamber too far, andto extract the round in case of misfire, it being understood that theextraction of the empty cases is efiected by the pressure of the gasesas the bolt retracts.

The conventional extractor or that illustrated in Figure 1, isspring-operated and oscillates in its cavity in the bolt. It has asquare or perpendicular inner lip which abuts the inner peripheral edgeof the base of the cartridge when the bolt is in locked or firingposition, there being a space between the face of the bolt and thecartridge base which is objectionable for reasons that will be stated,and which the present invention seeks to eliminate, and thereby improvethe operation of the gun.

The lip of the conventional extractor does not maintain contact at alltimes with the rim of the cartridge, and the cartridge is free to travelwith respect to the lip as in cases where the bolt, in

closing, is stopped by the face of the cartridge chamber or that part ofthe barrel that surrounds the chamber, the round continuing to moveforward until the rim of the cartridge engages the inner lip of theextractor. This engagement, at times is with suflicient force to tearout a portion of the cartridge rim which may drop into the mechanism andcause malfunctioning of the gun. Again if the firing pin protrusion isthe maximum allowable and the wall of the primer is the minimumthickness allowable, a punctured primer may result which is alsoobjectionable and likely to cause malfunctioning of the gun by foulingthe firing pin hole in the bolt and by particles falling into themechanism.

The usual or spring operated extractor is so arranged with respect tothe bolt that if the round in being fed gets ahead of the extractor theextractor may dip under the cartridge rim and spring into properposition.

The present invention contemplates an extractor which is made rigid withthe bolt either by being made integral therewith or rigidly attachedthereto, and provided with a lip having a positive angle, that is to sayan inclined inner position so that when the round is stripped from thebelt and fed into the chamber by the forward action of the bolt the baseof the cartridge slips down the face of the bolt until its rim is caughtby the extractor and when the round straightens out as it is chambered,the rim is cammed down the inclined lip of the extractor until the baseof the cartridge is flush with the face of the bolt, thus closing theobjectionable space between the bolt and the cartridge when the bolt islocked in firing position.

In the drawings illustrating the invention:

Figure 1 is a horizontal section of a portion of the breech of a gunwith the breech bolt and extractor therein, in one of its positionsrelative to a round shown in the cartridge chamber, the arrangementbeing conventional.

Figure 2 is a similar view showing my improvement.

Figure 3 is a section of a forward end of the bolt showing a form inwhich the extractor is made separable from the bolt and held inoperative position by suitably positioned pins.

Referring to the drawings and particularly Fig. 1, numeral I designatesthe bolt and 2 the conventional spring operated extractor, while 3designates the breech portion of the gun. The extractor is rockablymounted in the cavity 4, upon pin 5, there being in the rear end of theextractor a socket 6, for the reception of a spring 1 exerting atendency to normally raise the front end of the extractor. The lip 8 ofthe extractor is perpendicular or normal to the axis of the gun asindicated at 9 and lies flush against the rim ID of the cartridge whenthe bolt is in firing position, there being at such time a space I Ibetween the face [2 of the bolt and the base of the cartridge case. Thisis usual and is the construction upon which I aim to improve.

My arrangement in its preferred form is shown in Figure 2 in which theextractor I3 is an integral part of the bolt and extends beyond itsfront end a distance about the same as that which characterizes theextractor shown in Figure 1. Beyond the making of the extractor rigidwith the bolt the leading feature of the invention is, as intimated, theprovision of a novel lip of the extractor, which I form with a positiveangle [4 which functions as a cam to automatically cam the cartridgeback against the face of the bolt and thus close the space between thebolt and the cartridge, so that when the bolt is locked in firingposition the base of the cartridge is flush against the bolt. By thisarrangement the distance between the end of the firing pin and primer ofthe cartridge is uniform and can be extending from the front of the boltfor a distance suitable for the accommodation of the: extractor.Transverse pin holes are provided in the bolt and adapted to registerwith corresponding holes '1! in the extractor, the holesbeing.forlthereception.

for pins 18 by which the extractor and bolt are rigidly united. Anadvantageof the structure is that the extractor is replaceable in caseof injury or breakage.

As the cartridge base passes down over the face of the bolt instraightening out while being fed into the cartridge chamber, the rim ofthecartridg'eengages the inclined lip 14 and will be cammed 1back'againstthe front end of the bolt, Raga-inst which it remains untilthe round is fired. It will be noted that the type of cartridge casewith which the extractor is designed to be used is constructed with ataper toward the front. This-permits considerable leeway and play untilthe moment when the cartridge is firmly seated. There is also a slightamount of play in the bolt and other parts of the gun, so that inpractice no diificulty is encountered in obtaining the propercooperation of the parts necessary for correct operation within theusual range of tolerances encountered; The radial distance between thecenter of the'gun bore and the bottom of lip M isso designed that withthe usual tolerances the base of the cartridge is easily maintained,there being sufficient radial play under the worst permissibleconditions to allow rim-l0 to move down to snug engagement with bothface l2 of the bolt and cam surface [4 of extractor I 3.-

It should be noted in Figure 3 that the front face of the extractor lipI3 is rounded, which serves the purpose of allowing the cartridge caseto be cammed into the proper position-inthe event that the round is everfed ahead of the extractor, whichrarely occurs. This feature wassuccessfully tested by the inventor who partially pre positioned a roundin the chamber by hand and then released the bolt from a cockedposition.

The tare-positioned round was fired and extracted successfully.

not heretofore mentioned. The extractor'is much stronger at the base ofthe lip owing to the positive angle, than is the conventional extractor.Also, the integral extractor has neither extractor spring nor pin, whichin the conventional extractor are subject to breakage.

Different calibers in various types of guns may make it desirable tovary the positive angle of the extractor depending upon the particularweapon. For instance, while a 45 angle in the illustrated example of theinvention would be desirable in one "type of gun, a 15 angle may workbetter for another type of weapon, the object beingin all cases toeliminate the space between the face of the bolt and the cartridge Whenthe bolt is locked in firing position.

I claim:

Inqa machine gun, the combination of a reciprocating bolt having a boltface substantially perpendicular to the path of movement of the bolt andan extractor secured to said bolt, said extractor having arigidandunyielding -extension projecting beyondthe face of the bolt in adirection parallel to the path of'movement of the" same, said extractorextension and bolt faceto; gether providing a groove with the openen'd,thereof directed toward the bolt axis, saidgroove" having theforwardlydisposed side wall thereof bolt face.

GRAHAM B. NEIDHARDT;

REFERENCES CITED The following references are of record in the file -ofthis patent:

UNITED STATES PATENTS Number Name- Date 380,682 Holmes Apr. 10, 1888 J1,200,685 Young Oct. 10, '1916 1,544,566 Eickhoff July 7,1925 1,628,226Browning May 10, 1927 1,702,063 Swebilius' Feb. 12,1929 1,889,099 LoomisNov. 29, 1932" FOREIGN PATENTS Number Country Date 1,093 Great BritainApr. 10, 1869- 1,448 Denmark Jan. 29, 1898 13,117 Great Britain 1905'637,801 Germany Nov.-4, 1936

